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    <title>Document</title>
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    <script>
        // promise如何串连多个操作任务?
        // 原因是因为then或catch方法执行后都会继续返回一个新的promise对象，所以可以继续链式调用
        // 链式调用
        let p = new Promise((resolve, reject) => {
            resolve('OK');    
            //reject('error');
        });

        // 调用then方法
        p.then(v => {
            console.log(v);
            return "abc";
        }, r => {
            console.log(r);
        }).then(v => {
            console.log("Y", v);
        }, r => {
            console.log("N", r);
        });


    </script>
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